The Reborn! anime was originally a manga about a 7th grader named Tsuna Sawayoshi. He is utterly pathetic, no hope with girls, bad grades in school, gets made fun of, and so on. But all of that changes when he meets Reborn, a toddler hitman hired by Tsuna's mom to tutor him. Reborn is really trying to get Tsuna to join his rightful place as the tenth Vongola family boss, because all of the other hopefuls had died. Reborn has a gun that shoots different bullets, one of which is a deathperation shot. That bullet is what he uses to make Tsuna become hyper and much more powerful, however, it can only be used when Tsuna has total regret about his life. Reborn shoots Tsuna with the Deathperation shot, after Tsuna is hating his life after he did horrible in the volleyball game and suddenly Tsuna dies, and is reborn. He strips his clothes off so he has only underwear on(with hearts, I believe) and he is hyper. He is attacking the ball with his entire body, and his team wins the game.
Next, Reborn uses the gun to get Tsuna to ask out the girl he likes, Kyoko Sasagawa.
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